As a method for manufacturing a ceramic honeycomb structure, there is widely used a method where extrusion forming is conducted by the use of a die for forming a honeycomb structure, the die having back holes for introducing forming raw material (clay) and lattice-shaped slits communicating with the back holes. The die generally has an introduction portion where a plurality of back holes are open in a large area on a surface (introduction face) on one side and a forming portion where slits having a width corresponding with partition wall thickness of the honeycomb structure are provided in a lattice shape or the like on a face (the other face) on the opposite side. The back holes are generally provided so as to correspond with the positions where the slits of a lattice shape or the like cross, and the back holes and the slits communicates with each other inside the die. Therefore, a forming raw material such as ceramic raw material introduced from the back holes moves from the back holes, which have a relatively large inner diameter, to the narrow slits and is extruded as a honeycomb structure formed body from opening portions of the slits.
As such a die for forming a honeycomb structure, there has been used a plate-like member constituted of one kind of alloy such as stainless-steel alloy and sintered hard alloy, or a plate-like member formed by bonding two different kinds of plate-like members (see, e.g., Patent Documents 1 to 4).
Patent Document 1: JP-A-2000-326318
Patent Document 2: JP-A-2003-285308
Patent Document 3: JP-A-H10-315213
Patent Document 4: JP-A-2006-51682